使用LVM方式扩容硬盘空间
目录
[显示]环境说明
案例环境说明：该解码引擎服务器已经采用LVM的方式进行了部署，原始的解码引擎遇到/data硬盘空间不足的问题，需要通过LVM方式再次对/data扩展空间。如图所示，在我们的解码服务器上新增了一块硬盘，空间大小为5G。
[root@EZSonar ~]# fdisk -l
显示内容如图所示，新增硬盘为/dev/sdb。
第一步：新建一个分区
[root@EZSonar ~]# fdisk /dev/sdb
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n //添加新分区
Command action
e extended (说明：扩展分区)
p primary partition (1-4) (说明：主分区)
e //增加扩展分区
Partition number (1-4): 1
First cylinder (1-652, default 1)::<<ENTER
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-652, default 652): <<ENTER //也可以指定大小+5G，如果直接输入回车则使用所有空间
Using default value 652
Command (m for help): p //查看分区详情，可以看到新建的扩展分区
Disk /dev/sdb: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa9b024b3
Device Boot Start End Blocks Id System
/dev/sdb1 1 652 5237158+ 5 Extended
Command (m for help): n
Command action
l logical (5 or over)
p primary partition (1-4)
l
First cylinder (1-652, default 1): <<ENTER
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-652, default 652): <<ENTER
Using default value 652
Command (m for help): p
Disk /dev/sdb: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa9b024b3
Device Boot Start End Blocks Id System
/dev/sdb1 1 5 40131 5 Extended
/dev/sdb5 1 5 40099+ 83 Linux
Command (m for help): t //修改分区格式，下面选的5是上面的sdb5，默认格式是Linux
Partition number (1-5): 5
Hex code (type L to list codes): 8e
（说明：8e为Linux LVM格式的编码）
Changed system type of partition 5 to 8e (Linux LVM)
Command (m for help): p //查看分区情况
Disk /dev/sdb: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa9b024b3
Device Boot Start End Blocks Id System
/dev/sdb1 1 5 40131 5 Extended
/dev/sdb5 1 5 40099+ 8e Linux LVM
Command (m for help): w // 保存分区
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
1、 创建物理卷pv。
[root@EZSonar ~]# pvcreate /dev/sdb5 // 创建pv
Physical volume "/dev/sdb5" successfully created
[root@EZSonar ~]# pvdisplay /dev/sdb5 // 查看pv
-- "/dev/sdb5" is a new physical volume of "5.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb5
VG Name
PV Size 5.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID Hjoga4-EXmd-G53T-vAvQ-kDtA-60e2-vEHzBY
2、 查看已有的VG配置详情
[root@EZSonar ~]# vgdisplay
--- Volume group ---
VG Name vg_ezsonar
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 31.80 GiB
PE Size 4.00 MiB
Total PE 8141
Alloc PE / Size 8141 / 31.80 GiB
Free PE / Size 0 / 0
VG UUID JXOpXA-jkl5-Jdfp-IHeS-6MpP-8V3q-Vl3lMh
3、 增减逻辑卷
[root@EZSonar ~]# vgextend vg_ezsonar /dev/sdb5 // 扩展vg 将pv加入到vg_ezsonar
Volume group "vg_ezsonar" successfully extended
[root@EZSonar ~]# vgdisplay //查看VG情况
--- Volume group ---
VG Name vg_ezsonar
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 5
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 2
Act PV 2
VG Size 71.80 GiB
PE Size 4.00 MiB
Total PE 18380
Alloc PE / Size 8141 / 31.80 GiB
Free PE / Size 1023 / 5.00 GiB //剩余分配空间
VG UUID JXOpXA-jkl5-Jdfp-IHeS-6MpP-8V3q-Vl3lMh
4、 确认需要扩容的分区，红色/data分区需要扩容
[root@EZSonar ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_ezsonar-LogVol02
14G 3.7G 9.2G 29% /
tmpfs 939M 0 939M 0% /dev/shm
/dev/sda1 194M 33M 152M 18% /boot
/dev/mapper/vg_ezsonar-LogVol01
11G 2.2G 8.0G 22% /data
/dev/mapper/vg_ezsonar-LogVol00
8.0G 82M 8.0G 1% /var
5、 进行扩容
[root@EZSonar ~]# lvextend -L +5G /dev/mapper/vg_ezsonar-LogVol01 //扩展5G到lv:logVol01
Extending logical volume LogVol01 to 15.18 GiB
Logical volume LogVol01 successfully resized
[root@EZSonar ~]#[root@EZSonar ~]# resize2fs /dev/mapper/vg_ezsonar-LogVol01 //执行该重设大小
[root@EZSonar ~]# mount //查看挂载情况，原有分区采用什么文件格式
/dev/mapper/vg_ezsonar-LogVol02 on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext4 (rw)
/dev/mapper/vg_ezsonar-LogVol01 on /data type xfs (rw)
/dev/mapper/vg_ezsonar-LogVol00 on /var type xfs (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
[root@EZSonar ~]# xfs_growfs /dev/mapper/vg_ezsonar-LogVol01 //xfs文件格式采用xfs_growfs
meta-data=/dev/mapper/vg_ezsonar-LogVol01 isize=256 agcount=4, agsize=666880 blks
= sectsz=512 attr=2, projid32bit=0
data = bsize=4096 blocks=2667520, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 2667520 to 3978240
5、查看扩容结果
[root@EZSonar ~]# df –h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_ezsonar-LogVol02
14G 3.7G 9.2G 29% /
tmpfs 939M 0 939M 0% /dev/shm
/dev/sda1 194M 33M 152M 18% /boot
/dev/mapper/vg_ezsonar-LogVol01
16G 2.2G 13G 15% /data
/dev/mapper/vg_ezsonar-LogVol00
8.0G 82M 8.0G 1% /var
附录，对根分区进行扩容
首先确认VG有剩余空间可用
[root@EZSonar ~]# vgdisplay
--- Volume group ---
VG Name vg_ezsonar
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 6
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 2
Act PV 2
VG Size 41.79 GiB
PE Size 4.00 MiB
Total PE 10699
Alloc PE / Size 9421 / 36.80 GiB
Free PE / Size 1278 / 4.99 GiB //有5G剩余空间可用
VG UUID JXOpXA-jkl5-Jdfp-IHeS-6MpP-8V3q-Vl3lMh
[root@EZSonar ~]# mount //查看挂载情况，原有分区采用什么文件格式
/dev/mapper/vg_ezsonar-LogVol02 on / type ext4 (rw)
根分区采用ext4格式
[root@EZSonar ~]# lvextend -L +4.5G /dev/mapper/vg_ezsonar-LogVol02 /扩展4.5G到lv:logVol02
Extending logical volume LogVol02 to 18.12 GiB
Logical volume LogVol02 successfully resized
[root@EZSonar ~]# resize2fs /dev/mapper/vg_ezsonar-LogVol02
//ext4 文件格式采用resize2f
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg_ezsonar-LogVol02 is mounted on /; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 3
Performing an on-line resize of /dev/mapper/vg_ezsonar-LogVol02 to 8814592 (4k) blocks.
The filesystem on /dev/mapper/vg_ezsonar-LogVol02 is now 8814592 blocks long.
[root@EZSonar ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_ezsonar-LogVol02
18G 3.7G 14G 22% /
tmpfs 939M 0 939M 0% /dev/shm
/dev/sda1 194M 33M 152M 18% /boot
/dev/mapper/vg_ezsonar-LogVol01
16G 2.2G 13G 15% /data
/dev/mapper/vg_ezsonar-LogVol00
8.0G 82M 8.0G 1% /var
附录：LVM技术优势说明
优点
比起正常的硬盘分区管理，LVM更富于弹性：
§ 使用卷组(VG)，使众多硬盘空间看起来像一个大硬盘。
§ 使用逻辑卷（LV），可以创建跨越众多硬盘空间的分区。
§ 可以创建小的逻辑卷（LV），在空间不足时再动态调整它的大小。
§ 在调整逻辑卷（LV）大小时可以不用考虑逻辑卷在硬盘上的位置，不用担心没有可用的连续空间。It does not depend on the position of the LV within VG, there is no need to ensure surrounding available space.
§ 可以在线（online）对逻辑卷（LV）和卷组（VG）进行创建、删除、调整大小等操作。LVM上的文件系统也需要重新调整大小，某些文件系统也支持这样的在线操作。
§ 无需重新启动服务，就可以将服务中用到的逻辑卷（LV）在线（online）/动态（live）迁移至别的硬盘上。
§ 允许创建快照，可以保存文件系统的备份，同时使服务的下线时间（downtime）降低到最小。
这些优点使得LVM对服务器的管理非常有用，对于桌面系统管理的帮助则没有那么显著，你需要根据实际情况进行取舍。